Transport Effects on Capacitance-Frequency Analysis for Defect Characterization in Organic Photovoltaic Devices

Physical science relies on measurement, but what if measurements cannot be trusted? Capacitance spectroscopy, a common technique for studying defects in inorganic devices, has been adapted to probe organic photovoltaic devices (OPVs), yet without careful examination of its validity. The authors discuss conditions relevant to OPVs and show artifacts---including fictitious defects and spurious energy shifts---resulting from the low carrier mobility of organic materials. These findings will help to advance OPV technology, and offer fresh insight on the limitations of capacitance spectroscopy beyond OPVs.